This time, even the Israelis are worried that the locusts are out to get them. "They may not have ruined Pharaoh, but they could ruin us," one farmer, Tzachi Rimon, told Israel's Channel 10 TV.

Locust swarms have the potential to wipe out agricultural crops, and it's been eight years since such a serious assault has hit Egypt's Cairo region and Israel, said Keith Cressman, the senior locust forecasting officer at the U.N. Food and Agriculture Organization's headquarters in Rome.

"They came from the Sudan-Egypt border after breeding in December and January, flew north along the coast to nearly Suez, then got caught in some winds associated with a low-pressure system over the central Mediterranean to Cairo," Cressman told NBC News in an email. The weather system moved eastward, and on Monday, changing winds carried the swarm to the northern Sinai Peninsula and Israel's Negev Desert, he said.

A spokeswoman for Israel's Agriculture Ministry, Dafna Yurista, told The Associated Press that planes have gone out to spray pesticides on agricultural fields, to head off damage by a relatively small swarm of 2,000 locusts. Authorities called upon residents to be vigilant in reporting locust sightings.

Egypt's Ahram Online reported Sunday that locust swarms were attacking agricultural land in Suez, but other reports quoted Egyptian authorities as saying that the bugs were being "eradicated" and that no significant damage was being done to crops.

Cressman said the locusts of the Middle East don't follow the predictable kind of cycle that dictates the rise and fall of cicada swarms. "Outbreaks depend on rains in the desert, which are infrequent and irregular," he explained.

Photos of the locusts involved in the current outbreak suggest that these particular insects are "old and tired rather than young and hungry," Cressman said. If that's the case, this week's plague "will probably come to nothing," he said.

"However, there are other swarms that have moved from northeast Sudan and southeast Egypt to the Nile Valley in north Sudan, where they quickly matured and started laying eggs last week in winter crops," Cressman said. The eggs are expected to hatch in about a week, producing wingless nymphs that would become adult locusts in about six weeks. Those swarms could move into central Sudan and get a breeding boost from the summer rains that traditionally fall between June and September.

"Hence, there is good potential for locust infestations to increase," Cressman said. "If so, at the end of summer and late autumn, summer-bred swarms could move to the Red Sea coast of Sudan, Egypt, Eritrea and Saudi Arabia. I may be off very shortly to Khartoum [in Sudan] to discuss these implications with the government."

To learn more about the locusts of the Middle East, as well as infestations past, present and future, browse through the online resources at the FAO's Locust Watch website.